President Trump says he is sending military troops to guard the border with Mexico to prevent migrants’ illegal entry.

Trump went into an absolute tizzy when he learned that a caravan of immigrants from Central America — about 1,200 of them — had entered Mexico bound for the border with the United States. “Until we can have a border wall and security, we will monitor our border with our armed forces,” he said.

But his decision last week was a surprise even to military officers, ordered to send the National Guard to enforce our immigration laws.

The reality is that the caravan, called Viacrucis Migrante, is a symbolic march that has taken place every year since 2010 to make known to the world the challenges migrants endure when they pass through Mexico.

The reality is that the caravan, which on March 25 left the Mexican town of Tapachula in the south, was stopped in its attempt to cross Mexico. But by then, Trump was off and running.

Trump said his threats prompted the Mexican government to halt the caravan, but the organizers denied that the Mexican authorities had pressured them to end their trek. Irineo Mujica, director of Pueblo Sin Fronteras, which organizes the annual caravans, said the decision not to continue moving toward the border was because of the high number of participants and disorganization.

The participants were mostly from Honduras, a country plagued by poverty and gang violence, and where instability has only increased since President Juan Orlando Hernández was re-elected in a referendum tarnished by allegations of fraud.

In the caravan came women with children, women who are pregnant, and poor people with the hope of reaching the United States to work and help their families in Honduras. If Trump and his supporters consider that group a threat, it’s clear they don’t know the definition.

Undoubtedly, borders must be monitored, and immigration must be controlled. Trump is right on that point. But his method is the problem. The United States is not facing a massive migration crisis. In fact, U.S. Customs and Border Protection reported record-low apprehensions at the southwestern border in 2017.

So what’s the point of sending the National Guard to the border, with no thought to cost, approach or effectiveness? The point is, this is for show — Trump’s expensive and needless move to force Congress to fund his even more expensive, more needless border wall.

The border, indeed, has been militarized in recent years. President Obama sent 1,200 soldiers to fight drug trafficking. His predecessor, George W. Bush, sent about 6,000 troops for construction of fences and roads. The cost to taxpayers in both instances was astronomical.

Trump’s criticism of the immigration policies of his predecessors is getting old. Obama never implemented an open-border policy, as Trump has claimed. In fact, during the first seven years of his administration, Obama deported more than 2.7 million foreigners, the highest figure in U.S. history, which earned him the derisive nickname, “Deporter-in-Chief.”

Here’s what’s clear: The obsolete American immigration system must be overhauled.

We must seek comprehensive, and humane, immigration reform, and not militarize the border to block the passage of desperate people, much less a human deluge that doesn’t exist.